Elevator



E. P. COLLINS. ELEVATOR. APPLICATION FILED MI. 17, I919- Patented Mar.15, 1921.-

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ELEVATOR. APPLICATION FILED JAN. 17, 1919.

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ELEVATOR.

Specification of Letters Patent.

Patented Mar. 15, 1921.

Original application filed March 19, 1917, Serial No. 155,646. Dividedand this application filed January To all whom it may concern Be itknown that I, EDWARD P. COLLINS, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented certain new and useful Improvements in Elevators, of which thefollowing is a specification.

This invention relates to elevators, and more particularly to electricelevators which are used for cranes for hoisting various material andmachinery. It has for its object the production of an improved limitswitch to be used with such cranes or other similar apparatus, and it isa division of Patent No. 1,311,262, issued to me on July 29, 1919.

Of the accompanying drawings Figure 1 is an elevation, more or lessdiagrammatic of an electric elevating system comprising limit-switchmeans, which embody features of my invention. Fig. 2 is a section alongthe line 2-2 of Fig. 1. Fig. 3 is a detail diagrammatic view of themotor controller of the system; and Fig. 4 illustrates the variouselectric working circuits of the system.

I use in this instance a cylindrical form of motor controller 1, thecylinder being adapted to be rotated a limited distance in eitherdirection from the neutral position, and having fingers 2 fixed to theframe of the controller and extending over the cylinder so as to come incontact with the contact plates 3, 4, 5, and 6, fixed to the surface ofthe cylinder; and thus to produce the desired changes in wireconnections, various wires of the electric circuits being permanentlyconnected with the fingers.

Various contact plates are electrically connected with each other in anysuitable manner. For convenience I have in this instance indicated diarammatically the connections by the lines? to 14 inclusive. Thus all ofthe plates 3 are connected, also all of plates 4, and all of plates 5;while plates 6 are connected in pairs.

The supply mains 15 and 16 of the system are connected to the mainswitch 17 From this switch, wire 18 is connected with finger 19 througha switch 45, hereinafter described; while wire 20 is connected with afinger 21 through a switch 22 and wire 23. Wire 20 is also connectedwith finger 25 through coils 41 and 40 and wire 27.

In starting the motor, a switch 67 is closed and-this closes a relaycircuit through Serial No. 271,601.

coil 68, Wire 69, overload switch 75, wire 79, overload switch 26, wire90, and wire 20 to the main switch. This circuit energizes coil 68 whichcloses switch 45. Then, as the controller plates 3 are turned toward thefingers 2, plates 28 and 29 come in contact respectively with fingers 19and 30, and a circuit is formed from the wire 16, through wire 18,switch 45, coil 91, plate 28, plate 29, finger 30, resistances 98,finger 31, wire 32, brake coil 33, field coil 34, the low resistancecoils 35 and 36 hereinafter described, armature coils 37, wire 38,finger 94, plates 5, finger 21, wire 23, and, as soon as the switch 22is closed, the circuit will be complete, forming a series connectedmotor system. But at the same time the armature is shortened by thefollowing circuit: from coil 35 to plate 56, brush 57, plate 58, wire59, plate 60, brush 61, plate 62, wire 63, finger 64, plate 76, wire 9,plate 78, and finger 21.

The switch 22 is adapted to eliminate the heavy sparking current fromthe controller contacts. This switch remains open until plate 39 comesin contact with finger 25. Current then flows from the supply wire 16,throughfinger 19, plates 28 and 39, finger 25, wire 27, resistance coil40, electromagnet coil 41, and wire 20 to the supply wire 15. Thiscauses the electromagnet 42 to close the switch 22, and thus to closeboth of the above described circuits.

In case of an overload, at any time, coil 43 opens the switch 26, orcoil 91 opens the switch 75, breaking the circuit through coil 68, andreleasing switch 45 which is forced open by the spring 99. Switch 67 isnormally forced open by the spring 111, the current through coil 68 andthe lamp 112 being sufficient to hold switch 45 closed after it has beenclosed by manually closing switch 67 and shorting the lamp.

Coil 36 is also shorted by the above specified circuit through wires 59and 63. Hence this coil receives substantially no current; but coil 35is fully energized, and core 80 is pulled thereby inwardly and brush 61passes from plate to plate 84, thus opening the circuit through wire 63which shorted coil 36 and the armature. Then coil 36 becomes fullyenergized and core 81 is pulled inwardly and brush 57 changes from plate58 to plate 85. The shifting of the brushes 61 and 57in the abovedescribed manner connects the safety switch with the source of electricsupply for purposes hereinafter described. I

By shorting coil 36 and the armature coils, as stated, the brake coil 33receives sufiicient current to fully overcome the inertia and anysticking of the parts, and to thus fully release the brake. After theshorting circuit is opened by. the energized coil 35 shifting brush 61,the brake coil receives less current but sufficient to keep the brakeband released. By'this means I am able to reduce the amount of currentused by the brake coil and still have ample to fully release the brake.i

As the controller cylinder is rotated farther, the resistances 98 aregradually cut out by the respective plates 3 coming in contact with thefingers 2, until finally substantially the full line electromotive forceis effective through the motor, as indicated by the raising circuit ofFig. 4. v The motor is brought to rest by throwing the controller to theneutral position indicated by Fig. 3. This disconnects the supply lines,and coils 35 and 36, being d energized, the respective springs 92 and 93force the brushes 61 and 57 to plates '60 and 58. The carrier is thenlowered by reversing the motor and at the same time connecting it as ashunt motor. This is accomplished by bringing plates 4 into operation.As plate ,46 touches finger 19 a circuit is formed through wire 8,)late'47, finger 48, resistance coil 49, finger 31, wire 32, to thebrake and the field coils 33 and 34, and to coil 35. Also from. finger48 through the remainder of the resistances 98, finger 30, wire 50, theadjustable resistances 51, finger '52, plate 53,,wire10, plate 54,finger 94, wire 38, armature coils 37 to coil 36. Hence the field andarmature coils are in. parallel. From coils 35 and .36, where the fieldand armature circuits join, the current is free to flow through wire 55,plate 56, brush 57, plate 58, wire 59, plate 60, brush 61,.plate 62,wire 63, finger 64, plate 65, wire 11, plate 66, finger 21, wire 23,and, when the switch 22 is closed, through the switch, wire 20 andswitch 17 to the supply. Switch 22 is closed as beforeas soon as plate73 touches finger 25. See the lowering circuit, Fig. 4. As thecontroller cylinder is rotated further the resistances 98 are graduallycut out of the armature circuit and into the field circuit by the plates4 coming successively in contact with the fingers 2. If, now, it isdesired-to stop the motor with the carrier. and its load suspended, thecontroller is thrown back into neutral position, thus cutting off thesupply current. Simultaneously with the cutting off of the supplycurrent, a dynamic-brake circuit is f closed through the armature andthecontroller, as follows: from the armature coils 37, through wire 38,to finger 94, plates 54 and 53, finger 52, coil 51, finger 30,resistances 98, finger 31, wires 14 and 24, field coil 34, "coils 35 and36 to the armature; thus shorting the electrically operated mechanicalbrake coil and thus applying the mechanical brake and allowing the loadto come to rest under the retarding action of the mechanical brake andalso of the dynamic brake formed by the closed circuit through thearmature. See the braking circuit, Fig. 4.

It is customary with elevators, cranes and other hoisting mechanism tohave limit switches, and especially switches limiting the height towhich the carrier can be raised. Switches for this purpose may benormally closed or open. I prefer for the purposes of illustrating myinvention to use a normally open switch, which, when the height limit isreached, is closed by the carrier or otherwise, and thus stops themotor. In this instance I arrange the system so thatwhen the switch isclosed the motor armature coils are shorted and hence the motor isbrought to rest.

Referring to Fig. 1, when elevating, the armature 37, by means of thecontroller 1, is connected in series with the field coil 34 of themotor, in the manner hereinabove described. Switches 57 and 61 are thenheld, by the coils 36 and 35, respectively in contact with plates 84 and85, as the coils are arranged so: as to cause the adjacent ends of thecores and '81 to have unlike polarity and hence to attract each other.The outer ends of the coils 36 and 35 are connected, by means of thewires 97 and 96, respec tively, with the :arms 103 and 104 of the limitswitch 100. This switch is arranged to be operated by means of the screw101, which is operatively connected .to thedruin shaft 1.02, or isoperated in any other suitable manner. The arms 103 and 104 are arrangedto be shorted by a plate 105. This plate is mounted on pivoted levers106 which are respectively arranged to be operated by the pivoted levers107. These levers are all pivoted to a non-rotatable block 108 intowhich is threaded the screw shaft 101, while trips 109 are arranged tooperate the levers 107 at the proper time. As the load rises, the block108 is forced to the right by the drum shaft, and the levers 107, andthus also the levers 106, are operated by the respective trips 109against the centering springs 110, thus moving the plate 105 away fromthe arms 103 and 104 until the trip 109 is passed. When the trip ispassed the plate 105 will fly to the right and short the arms 103' and104. Coils 35 and 36 will thus be shorted, and the respective springs 92and 93 will pull the switches 61 and 57 back tothe respective plates 60and 58, as

from the main lead 16, through switch 17 wire 18, switch 45, wire 91,plate 28, wire 7, wire 32, brake 33, field coil 34, point 74:, coil 35,and then around the armature through the wire 55, switch 57, wire 59,switch 61, wire 63, plate 76, wire 23, overload circuit breaker coil 43,switch 22, to the main 15. This will bring the motor to rest. Also thecurrent will then flow through coils 35 and 36 in the oppositedirections, as follows: From the point 74: the current will flowdirectly through coil 35 without change in direction; but it will alsoflow through wire 96, the limit switch and wire 97, through coil 36 inthe opposite direction; hence the adjacent ends of the cores SO and 81will have like polarity and will be repelled, holding the switches 61and 57 in position as shown in Fig. 1.

The motor will then be stopped not only because its armature receivessubstantially no current, but, as soon as the switches 61 and 57 areshifted, a dynamic brake will be set up in the armature circuit which isnow closed, independent of the main circuit, through the above describedshorting circuit, as the field coil will be still fully energized, as isshown by the stopping circuit of Fig. 4.

It will be seen, however, that closing of the limit switch, and shiftingthe switches 57 and 61, in no way interferes with lowering the elevatorcarrier. The operator has only to throw the controller back to neutral,and then to the lowering position, and the normal lowering circuit willbe formed, it being then immaterial whether or not the limit switch 100is shorted, as the springs 92 and 93, and the unlike adjacent poles ofthe cores S0 and 81, will hold the switches 61 and 57 in the loweringposition. However, a material current will flow through the shortingwires 96 and 97 and the limit switch 100, and to avoid sparking whenthis circuit is opened as the load descends, the trip 109 is arranged,as shown, to make a quick opening of the switch as well as a quickclosing.

It is to be understood that this limit switch may be used in conjunctionwith any other form of limit switch, such as the common form of switch70, which is supported by the arm 86 in the path of motion of the pin 72 fixed to the carrier 71; so that when the pin strikes the switch itwill be closed and the motor armature will be shorted by the wires 87and 88, which take the place of the wire 59. These switches may bearranged to act simultaneously or successively; but, as in case ofeither switch the armature is shorted, it is to be understood that iteither limit switch operates, the motor will be stopped. Althoughclosing of switch 70 will not operate switches 61 and 57, as the currentis not then reversed through coil 36, yet the dynamic brake oi the motorwill be effective "through the shorting circuit which is closed on thearmature.

I claim as my invention:

1. In an elevating system, operating means, a limit switch comprising aslidably mounted member operatively connected with said operating means,a lever pivoted to said member, a trip fixed in position in the path ofmotion of one end of said lever, two electric switch arms fixed inposition, a metal-- lic plate mounted on said member and arranged to beoperated by said lever, both of said arms being in the path of motion ofsaid plate, and resilient means tending to hold said lever in normalposition.

2. In an elevating system an electric limit switch comprising fixedterminals to be shorted, a piece arranged to be moved toward saidterminals, a member to short said terminals movably mounted on saidpiece, means for moving said member with relation to said piece awayfrom said terminals as said piece approaches said terminals, and meansfor then bringing said member quickly back to its normal position withrelation to said piece when said piece is adjacent said terminals.

In testimony wheroo'f I hereunto set my hand.

EDWARD P. COLLINS.

